PROBLEM TO BE SOLVED: To provide a simple and low-cost hot water supply device capable of stably providing prescribed-temperature and prescribed-pressure hot water to broad city water pressure, and suppressing wasteful power consumption according to pressure of low-temperature water supplied from city water piping or the like and high-temperature water supplied from a water heater.SOLUTION: An automatic mixing valve 1 mixing low-temperature water supplied from city water piping or the like and high-temperature water supplied from a water heater to prescribed temperature, a pump 4 pressurizing hot water mixed in the automatic mixing valve 1 to prescribed pressure or greater, a first pressure reducing valve 6 decompressing the hot water pressurized in the pump 4 to predetermined pressure are connected by piping 9.
